S-90403A878 M8 x 20 mm ASME B18.13.1M Steel Pan Head Phillips Screws with Internal-Tooth Lock Washer

Key Features & Benefits at a Glance

• Superior vibration resistance with integrated internal-tooth lock washers that maintain secure fastening in high-stress environments
• Enhanced corrosion protection through zinc-plated steel construction for extended service life in industrial conditions
• Optimized drive engagement with Phillips No. 4 drive design enabling efficient installation and reduced cam-out risk
• Reliable thread performance featuring Class 6g coarse threads that provide quick assembly and excellent holding power
• Robust mechanical strength delivering 60,000 psi tensile strength and Rockwell B73 hardness for demanding applications
• Full-thread design ensuring maximum grip length and uniform stress distribution along the entire fastener
• Standard-compliant manufacturing meeting ASME B18.13.1M specifications for consistent quality and dimensional accuracy

Professional Applications & Engineering Value

These M8 rounded head screws with internal-tooth lock washers address critical vibration-induced loosening challenges in industrial machinery, automotive assemblies, and electrical enclosures. The zinc-plated steel construction provides essential corrosion resistance while maintaining the 60,000 psi tensile strength required for structural applications. The coarse thread with 1.25mm pitch ensures rapid installation and reliable performance in various materials, while the pan head profile with Phillips drive offers streamlined installation without protruding hardware. Engineered to withstand dynamic loads and environmental exposure, these fully threaded metric screws deliver long-term reliability in manufacturing, maintenance, and equipment assembly operations where vibration resistance and consistent clamping force are paramount.

Specification Summary & Compliance

Manufactured to precise metric dimensions with Class 6g thread fit tolerance ensuring compatibility with standard metric nuts and threaded components. These rounded head screws comply with ASME B18.13.1M mechanical and dimensional specifications, guaranteeing interchangeability and performance consistency. The product meets RoHS 3 (2015/863/EU) compliance for restricted substance control and REACH (EC 1907/2006) regulations for chemical safety, making them suitable for global industrial applications with environmental compliance requirements.